From a2e8e3090c992402fb8723761319cb03e4b5f9ef Mon Sep 17 00:00:00 2001
From: Malcolm Jestadt <MalcolmJestadt@gmail.com>
Date: Sun, 17 Jan 2021 03:45:56 -0500
Subject: [PATCH] SPU LLVM: Optimize FSM following comparison - FSM following a
 comparison instruction can be optimized to a single shuffle instruction

---
 rpcs3/Emu/Cell/SPURecompiler.cpp | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/rpcs3/Emu/Cell/SPURecompiler.cpp b/rpcs3/Emu/Cell/SPURecompiler.cpp
index 5dd6730316..460c2bf00d 100644
--- a/rpcs3/Emu/Cell/SPURecompiler.cpp
+++ b/rpcs3/Emu/Cell/SPURecompiler.cpp
@@ -6463,6 +6463,23 @@ public:
 
 	void FSM(spu_opcode_t op)
 	{
+		// FSM following a comparison instruction
+		if (match_vr<s8[16], s16[8], s32[4], s64[2]>(op.ra, [&](auto c, auto MP)
+		{
+			using VT = typename decltype(MP)::type;
+
+			if (auto [ok, x] = match_expr(c, sext<VT>(match<bool[std::extent_v<VT>]>())); ok)
+			{
+					set_vr(op.rt, (splat_scalar(c)));
+					return true;
+			}
+
+			return false;
+		}))
+		{
+			return;
+		}
+
 		const auto v = extract(get_vr(op.ra), 3);
 		const auto m = bitcast<bool[4]>(trunc<i4>(v));
 		set_vr(op.rt, sext<s32[4]>(m));